Author
He Zhu
Other affiliations: University of Queensland, South China University of Technology
Bio: He Zhu is an academic researcher from University of Technology, Sydney. The author has contributed to research in topics: Band-pass filter & Wideband. The author has an hindex of 18, co-authored 74 publications receiving 922 citations. Previous affiliations of He Zhu include University of Queensland & South China University of Technology.
Topics: Band-pass filter, Wideband, Resonator, Stopband, Passband
Papers
More filters
TL;DR: In this paper, the authors proposed a method of suppressing cross-band scattering in dual-band dual-polarized antenna arrays by introducing chokes into lowband (LB) elements to suppress high-band (HB) scattering currents.
Abstract: This paper presents a novel method of suppressing cross-band scattering in dual-band dual-polarized antenna arrays. The method involves introducing chokes into low-band (LB) elements to suppress high-band (HB) scattering currents. The experimental results show that by inserting LB-pass HB-stop chokes into LB radiators, suppression of induced HB currents on the LB elements is achieved. This greatly reduces the pattern distortion of the HB array caused by the presence of LB elements. The array considered is configured as two columns of HB antennas operating from 1.71 to 2.28 GHz interleaved with a single column of LB antennas operating from 0.82 to 1.0 GHz. The realized array with choked LB element has stable and symmetrical radiation in both HB and LB.
95 citations
TL;DR: In this article, a band-notched ultra wideband (UWB) slot antenna with bandnotched characteristics is proposed, where a stepped slot is adopted as a radiator to realize UWB impedance matching and reduce the antenna size.
Abstract: A compact ultra-wideband (UWB) slot antenna with band-notched characteristics is proposed. A stepped slot is adopted as a radiator to realize UWB impedance matching and reduce the antenna size. By slitting an open-ended quarter-wavelength split slot on the back of the feed and a short-ended half-wavelength split-ring slot near the stepped slot, a second-order notched band of 5.15-5.85 GHz is achieved. Compared with the traditional band-notched antenna, the selectivity of the notched band is greatly improved and size of the antenna is reduced at the same time. The volume of the antenna is only 22 mm×8.5 mm×0.8 mm. Besides, the bandwidth can be easily controlled by adjusting the lengths of the two slots respectively. Good agreement is achieved between simulated and measured results, which show that the proposed antenna has nice impedance matching and radiation pattern characteristics.
91 citations
TL;DR: In this article, a compact ultra-wideband (UWB) bandpass filter using dual-stub-loaded resonators (DSLR) is presented, which is analyzed by using the odd-and even-mode method.
Abstract: A compact ultra-wideband (UWB) bandpass filter using dual-stub-loaded resonators (DSLR) is presented. The DSLR is analyzed by using the odd- and even- mode method. Four resonant modes can be tuned by the DSLR in 3.1 GHz - 10.6 GHz, and a pair of transmission zeros can be generated at the lower and upper stopband when the DSLR is applied to a UWB filter. Therefore a UWB bandpass filter is realized with good skirt selectivity, harmonic suppression, as well as compact size. Finally the proposed filter is simulated and fabricated. The measured results are in good agreement with the predicted one, demonstrating this structure is feasible in practical use.
79 citations
TL;DR: In this article, a compact wideband four-way filtering PD is presented, which includes a pair of looped coupled-line structures to provide the needed power division to four output ports.
Abstract: A compact wideband four-way filtering PD is presented. The structure of the proposed device includes a pair of looped coupled-line structures to provide the needed power division to four output ports. Moreover, a pair of short-ended coupled-line stubs is used to introduce multiple transmission poles and transmission zeros for a sharp cut-off of the passband and high upper-stopband rejection. A detailed design procedure is shown to determine the initial design parameters. A prototype is designed, simulated and measured experimentally. The measured results show 56.5% bandwidth centered at 1.5 GHz with more than 15 dB upper-stopband rejection up to 4.15 GHz, more than 13 dB in-band isolation, and 15 dB return loss at all output ports.
73 citations
TL;DR: In this paper, a quadruplemode ultra wideband (UWB) bandpass filter with a notch-band and wide upper stopband is presented, which is realized using a ring resonator which is loaded with two sets of stubs, i.e., one is loaded in the center and two little stubs at the symmetrical side locations.
Abstract: A quadruple-mode ultra-wideband (UWB) bandpass filter with a notch-band and wide upper stopband is presented in this letter. The UWB filter is realized using a ring resonator which is loaded with two sets of stubs, i.e., one is loaded in the center and two little stubs at the symmetrical side locations. The loaded stubs are used to create transmission zeros in upper stopband thus high modes are suppressed greatly. Moreover, two identical via-loaded ring resonators are inserted within the stub-loaded ring resonator, to create a notch-band around 5-6 GHz to avoid WLAN signals. Two reflection poles appear in the notch-band, resulting in a switchable bandwidth of the notch-band. Finally, a UWB filter with a notch-band is simulated and fabricated, and measured results provide an experimental validation of predicted performance of the filter.
61 citations
Cited by
More filters
08 Dec 1998
TL;DR: In this article, the authors consider the unique features of UWB technology and propose that the FCC should consider them in considering changes to Part 15 and take into account their unique features for radar and communications uses.
Abstract: In general, Micropower Impulse Radar (MIR) depends on Ultra-Wideband (UWB) transmission systems. UWB technology can supply innovative new systems and products that have an obvious value for radar and communications uses. Important applications include bridge-deck inspection systems, ground penetrating radar, mine detection, and precise distance resolution for such things as liquid level measurement. Most of these UWB inspection and measurement methods have some unique qualities, which need to be pursued. Therefore, in considering changes to Part 15 the FCC needs to take into account the unique features of UWB technology. MIR is applicable to two general types of UWB systems: radar systems and communications systems. Currently LLNL and its licensees are focusing on radar or radar type systems. LLNL is evaluating MIR for specialized communication systems. MIR is a relatively low power technology. Therefore, MIR systems seem to have a low potential for causing harmful interference to other users of the spectrum since the transmitted signal is spread over a wide bandwidth, which results in a relatively low spectral power density.
644 citations
TL;DR: In this article, a dual-polarized millimeter-wave (mm-wave) patch antenna with bandpass filtering response is proposed, which consists of a differential-fed cross-shaped driven patch and four stacked parasitic patches.
Abstract: This article presents a novel dual-polarized millimeter-wave (mm-Wave) patch antenna with bandpass filtering response. The proposed antenna consists of a differential-fed cross-shaped driven patch and four stacked parasitic patches. The combination of the stacked patches and the driven patch can be equivalent to a bandstop filtering circuit for generating a radiation null at the upper band edge. Besides, four additional shorted patches are added beside the cross-shaped driven patch to introduce another radiation null at the lower band edge. Moreover, by embedding a cross-shaped strip between these four stacked patches, the third radiation null is generated to further suppress the upper stopband. As a result, a quasi-elliptic bandpass response is realized without requiring extra filtering circuit. For demonstration, a prototype was fabricated with standard PCB process and measured. The prototype operates in the 5G band (24.25–29.5 GHz) and it has an impedance bandwidth of 20%. The out-of-band gain drops over 15 dB at 23 and 32.5 GHz, respectively, which exhibits high selectivity. These merits make the proposed antenna a good element candidate for the 5G mm-Wave massive MIMO applications to reduce the requirements of the filters in the mm-Wave RF front ends.
88 citations
TL;DR: In this article, a structure of a compact ultra-wideband monopole antenna has been presented, which consists of a microstrip-fed rectangle radiator as well as a ground plane with a rectangle slit and an L-shaped stub.
Abstract: A structure of a compact ultra-wideband monopole antenna has been presented. The antenna consists of a microstrip-fed rectangle radiator as well as a ground plane with a rectangle slit and an L-shaped stub. The critical factor in achieving a small size is a careful design procedure involving numerical optimisation of all geometry parameters of the antenna aiming at explicit size reduction while maintaining acceptable electrical performance. The final design exhibits dimensions of only 9.45 × 18.5 mm and a footprint of 175 mm
2
. Experimental validation and comparisons with competitive designs are also provided.
85 citations
30 Jun 2021
TL;DR: In this article, the authors present a timely overview of the mainstream quasi-optical techniques employed in current and future multi-beam antennas, including both conventional and advanced lens and reflector based configurations to realize high gain multiple beams at low cost and in small form factors.
Abstract: Multi-beam antennas are critical components in future terrestrial and non-terrestrial wireless communications networks. The multiple beams produced by these antennas will enable dynamic interconnection of various terrestrial, airborne and space-borne network nodes. As the operating frequency increases to the high millimeter wave (mmWave) and terahertz (THz) bands for beyond 5G (B5G) and sixth-generation (6G) systems, quasi-optical techniques are expected to become dominant in the design of high gain multi-beam antennas. This paper presents a timely overview of the mainstream quasi-optical techniques employed in current and future multi-beam antennas. Their operating principles and design techniques along with those of various quasi-optical beamformers are presented. These include both conventional and advanced lens and reflector based configurations to realize high gain multiple beams at low cost and in small form factors. New research challenges and industry trends in the field, such as planar lenses based on transformation optics and metasurface-based transmitarrays, are discussed to foster further innovations in the microwave and antenna research community.
82 citations
TL;DR: In this article, a compact wideband four-way filtering PD is presented, which includes a pair of looped coupled-line structures to provide the needed power division to four output ports.
Abstract: A compact wideband four-way filtering PD is presented. The structure of the proposed device includes a pair of looped coupled-line structures to provide the needed power division to four output ports. Moreover, a pair of short-ended coupled-line stubs is used to introduce multiple transmission poles and transmission zeros for a sharp cut-off of the passband and high upper-stopband rejection. A detailed design procedure is shown to determine the initial design parameters. A prototype is designed, simulated and measured experimentally. The measured results show 56.5% bandwidth centered at 1.5 GHz with more than 15 dB upper-stopband rejection up to 4.15 GHz, more than 13 dB in-band isolation, and 15 dB return loss at all output ports.
73 citations